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Hydrodynamics and Heat Mass Transfer in Two-Phase Dispersed Flows in...
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Hydrodynamics and Heat Mass Transfer in Two-Phase Dispersed Flows in Pipes or Ducts

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Hydraulics and Hydrodynamics".

Deadline for manuscript submissions: closed (1 December 2022) | Viewed by 18328

Printed Edition Available!
A printed edition of this Special Issue is available here.

Special Issue Editors

Prof. Dr. Maksim Pakhomov

E-Mail Website
Guest Editor
Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Interests: numerical simulation; fluid mechanics; computational fluid dynamics; CFD simulation; heat and mass transfer; numerical modelling; thermal engineering; modelling and simulation; mechanical engineering; engineering; turbulent two-phase flows; droplets; bubbles
Special Issues, Collections and Topics in MDPI journals
Dr. Pavel Lobanov

E-Mail Website
Guest Editor
Institute of Thermophysics, Siberian Branch, Russian Academy of Sciences, Novosibirsk, Russia
Interests: measurements and experiments; turbulent flows; heat and mass transfer; engineering; nuclear thermal hydraulics; mechanical engineering
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

Two-phase gas–liquid flows are frequently encountered in energy, nuclear, chemical, geothermal, oil and gas, and refrigeration industries. Two-phase gas–liquid flows can occur in various forms, such as flows transitioning from pure liquid to vapor as a result of external heating; separated flows behind a sudden flow expansion or constriction, and dispersed two-phase flows where dispersed phase is present in the form of liquid droplets or gas bubbles in a continuous carrier fluid phase (i.e., gas or liquid). Typically, such flows are turbulent with a considerable interfacial interaction between the carrier fluid and the dispersed phases. The interfacial heat and mass transfer is very important in the modeling of such flows. The variety of flow regimes significantly complicates the theoretical prediction of hydrodynamics in the two-phase flow. Thus, the application of numerous hypotheses, assumptions, and approximations is required. The complexity of flow structure often makes it impossible to theoretically describe its behavior, and so empirical data are applied instead. The correct simulation of two-phase gas–liquid flows is of great importance for the safety and prediction of energy equipment elements.

Sincerely yours,

Prof. Dr. Maksim Pakhomov
Dr. Pavel Lobanov
Guest Editors

Manuscript Submission Information

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Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Water is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • two-phase dispersed flow
  • liquid droplets
  • gas bubbles
  • flow structure
  • heat and mass transfer
  • measurements
  • numerical modeling

Published Papers (12 papers)

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Editorial

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4 pages, 179 KiB  
Editorial
Hydrodynamics and Heat Mass Transfer in Two-Phase Dispersed Flows in Pipes or Ducts
by Maksim A. Pakhomov and Pavel D. Lobanov
Water 2023, 15(11), 1969; https://doi.org/10.3390/w15111969 - 23 May 2023
Viewed by 1071
Abstract
Two-phase gas-liquid and gas-dispersed flows are frequently encountered in energy, nuclear, chemical, geothermal, oil and gas and refrigeration industries [...] Full article
(This article belongs to the Special Issue Hydrodynamics and Heat Mass Transfer in Two-Phase Dispersed Flows in Pipes or Ducts)

Research

Jump to: Editorial, Review

23 pages, 8628 KiB  
Article
Effect of Wall Proximity and Surface Tension on a Single Bubble Rising near a Vertical Wall
by Raghav Mundhra, Rajaram Lakkaraju, Prasanta Kumar Das, Maksim A. Pakhomov and Pavel D. Lobanov
Water 2023, 15(8), 1567; https://doi.org/10.3390/w15081567 - 17 Apr 2023
Cited by 3 | Viewed by 1958
Abstract
Path instability of a rising bubble is a complex phenomenon. In many industrial applications, bubbles encounter walls, and the interactions between the bubbles and the wall have a significant impact on flow physics. A single bubble rising near a vertical wall was experimentally [...] Read more.
Path instability of a rising bubble is a complex phenomenon. In many industrial applications, bubbles encounter walls, and the interactions between the bubbles and the wall have a significant impact on flow physics. A single bubble rising near a vertical wall was experimentally observed to follow a bouncing trajectory. To investigate the near-wall dynamics of rising bubbles, 3D numerical simulations were performed based on the volume of fluid (VOF) method using the open source solver OpenFOAM. The effect of wall proximity and surface tension on the bubble trajectory was investigated. Previous studies have focused on the near-wall rising dynamics of bubbles for higher Eotvos numbers (Eo) and varied the Galilei number (Ga). The physical properties of the flow were chosen such that the free-rising bubble lies in the rectilinear regime. The Ga number was fixed and the Eo number was varied to analyze its effect on the bubble’s rising trajectory. It was found that the presence of the wall increases the drag experienced by the bubble and induces an early transition from rectilinear to a planar zigzagging regime. We identify the maximum wall distance and the critical Eo number for the bubble to follow a bouncing trajectory. The amplitude, frequency and wavelength of the bouncing motion are independent of the initial wall distance, but they decrease with decreasing surface tension. Full article
(This article belongs to the Special Issue Hydrodynamics and Heat Mass Transfer in Two-Phase Dispersed Flows in Pipes or Ducts)
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13 pages, 2326 KiB  
Article
Oil–Water Separation on Hydrophobic and Superhydrophobic Membranes Made of Stainless Steel Meshes with Fluoropolymer Coatings
by Alexandra Melnik, Alena Bogoslovtseva, Anna Petrova, Alexey Safonov and Christos N. Markides
Water 2023, 15(7), 1346; https://doi.org/10.3390/w15071346 - 30 Mar 2023
Cited by 3 | Viewed by 1980
Abstract
In this work, membranes were synthesized by depositing fluoropolymer coatings onto metal meshes using the hot wire chemical vapor deposition (HW CVD) method. By changing the deposition parameters, membranes with different wetting angles were obtained, with water contact angles for different membranes over [...] Read more.
In this work, membranes were synthesized by depositing fluoropolymer coatings onto metal meshes using the hot wire chemical vapor deposition (HW CVD) method. By changing the deposition parameters, membranes with different wetting angles were obtained, with water contact angles for different membranes over a range from 130° ± 5° to 170° ± 2° and a constant oil contact angle of about 80° ± 2°. These membranes were used for the separation of an oil–water emulsion in a simple filtration test. The main parameters affecting the separation efficiency and the optimal separation mode were determined. The results reveal the effectiveness of the use of the membranes for the separation of emulsions of water and commercial crude oil, with separation efficiency values that can reach over 99%. The membranes are most efficient when separating emulsions with a water concentration of less than 5%. The pore size of the membrane significantly affects the rate and efficiency of separation. Pore sizes in the range from 40 to 200 µm are investigated. The smaller the pore size of the membranes, the higher the separation efficiency. The work is of great economic and practical importance for improving the efficiency of the membrane separation of oil–water emulsions. It lays the foundation for future research on the use of hydrophobic membranes for the separation of various emulsions of water and oil products (diesel fuel, gasoline, kerosene, etc.). Full article
(This article belongs to the Special Issue Hydrodynamics and Heat Mass Transfer in Two-Phase Dispersed Flows in Pipes or Ducts)
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16 pages, 1886 KiB  
Article
An Impact of the Discrete Representation of the Bubble Size Distribution Function on the Flow Structure in a Bubble Column Reactor
by Alexander Chernyshev, Alexander Schmidt and Veronica Chernysheva
Water 2023, 15(4), 778; https://doi.org/10.3390/w15040778 - 16 Feb 2023
Cited by 1 | Viewed by 1424
Abstract
The purpose of the present study is to analyze the effect of different discrete representations of the continuous bubble size distribution function on the flow structure in a bubble column reactor. Poly- and monodisperse media were considered, such that the mathematical expectation of [...] Read more.
The purpose of the present study is to analyze the effect of different discrete representations of the continuous bubble size distribution function on the flow structure in a bubble column reactor. Poly- and monodisperse media were considered, such that the mathematical expectation of the bubble size in the polydisperse case was equal to the bubble size in the monodisperse case at the same volumetric bubble contents. For these computations the normalized variances of the velocity profiles of the carrier and the disperse phases, the volume fraction of the disperse phase, and the specific area of the interfacial surface were determined. The normalized variances were calculated from a reference scenario with a detailed resolution of the bubble size distribution function with ten bubble classes. It was shown that with increase of the average bubble sizes mono- and polydisperse approaches provide converging solutions. A modified hybrid discretization of the bubble size distribution function with four classes of bubbles was shown to predict the flow structure with normalized variance less than 5% over the entire computational domain for all monitored parameters. Full article
(This article belongs to the Special Issue Hydrodynamics and Heat Mass Transfer in Two-Phase Dispersed Flows in Pipes or Ducts)
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18 pages, 9154 KiB  
Article
Spreading of Impacting Water Droplet on Surface with Fixed Microstructure and Different Wetting from Superhydrophilicity to Superhydrophobicity
by Sergey Starinskiy, Elena Starinskaya, Nikolay Miskiv, Alexey Rodionov, Fedor Ronshin, Alexey Safonov, Ming-Kai Lei and Vladimir Terekhov
Water 2023, 15(4), 719; https://doi.org/10.3390/w15040719 - 11 Feb 2023
Cited by 6 | Viewed by 2328
Abstract
The spreading of the water droplets falling on surfaces with a contact angle from 0 to 160° was investigated in this work. Superhydrophilicity of the surface is achieved by laser treatment, and hydrophobization is then achieved by applying a fluoropolymer coating of different [...] Read more.
The spreading of the water droplets falling on surfaces with a contact angle from 0 to 160° was investigated in this work. Superhydrophilicity of the surface is achieved by laser treatment, and hydrophobization is then achieved by applying a fluoropolymer coating of different thicknesses. The chosen approach makes it possible to obtain surfaces with different wettability, but with the same morphology. The parameter t* corresponding to the time when the capillary wave reaches the droplet apex is established. It is shown that for earlier time moments, the droplet height change does not depend on the type of used substrate. A comparison with the data of other authors is made and it is shown that the motion of the contact line on the surface weakly depends on the type of the used structure if its characteristic size is less than 10 μm. Full article
(This article belongs to the Special Issue Hydrodynamics and Heat Mass Transfer in Two-Phase Dispersed Flows in Pipes or Ducts)
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11 pages, 14872 KiB  
Article
The Effect of the Angle of Pipe Inclination on the Average Size and Velocity of Gas Bubbles Injected from a Capillary into a Liquid
by Anastasia E. Gorelikova, Vyacheslav V. Randin, Alexander V. Chinak and Oleg N. Kashinsky
Water 2023, 15(3), 560; https://doi.org/10.3390/w15030560 - 31 Jan 2023
Cited by 1 | Viewed by 1618
Abstract
This work is devoted to an experimental study of the effect of coalescence on the average diameter and velocity of gas bubbles in an inclined pipe. The measurements were carried out for agas flow rate of 3.3 and 5 mL/min at pipe inclination [...] Read more.
This work is devoted to an experimental study of the effect of coalescence on the average diameter and velocity of gas bubbles in an inclined pipe. The measurements were carried out for agas flow rate of 3.3 and 5 mL/min at pipe inclination angles of 30–60°. The study of gas bubble diameters was performed using a shadow photography method. The values of the average diameter and velocity of the bubbles were obtained depending on the angle of inclination of the pipe. A map of regime parameters was constructed at which gas bubbles form a stable structure—a chain of bubbles with an equal diameter. Full article
(This article belongs to the Special Issue Hydrodynamics and Heat Mass Transfer in Two-Phase Dispersed Flows in Pipes or Ducts)
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11 pages, 6558 KiB  
Article
Evaporation Dynamics of Sessile and Suspended Almost-Spherical Droplets from a Biphilic Surface
by Elena Starinskaya, Nikolay Miskiv, Vladimir Terekhov, Alexey Safonov, Yupeng Li, Ming-Kai Lei and Sergey Starinskiy
Water 2023, 15(2), 273; https://doi.org/10.3390/w15020273 - 09 Jan 2023
Cited by 10 | Viewed by 2089
Abstract
Research in the field of the evaporation of liquid droplets placed on surfaces with special wetting properties such as biphilic surfaces is of great importance. This paper presents the results of an experimental study of the heat and mass transfer of a water [...] Read more.
Research in the field of the evaporation of liquid droplets placed on surfaces with special wetting properties such as biphilic surfaces is of great importance. This paper presents the results of an experimental study of the heat and mass transfer of a water droplet during its evaporation depending on the direction of the gravitational force. A special technique was developed to create unique substrates, which were used to physically simulate the interaction of liquid droplets with the surface at any angle of inclination to the horizontal. It was found that the suspended and sessile droplets exhibited fundamentally different evaporation dynamics. It was shown that the suspended droplets had a higher temperature and, at the same time, evaporated almost 30% faster. Full article
(This article belongs to the Special Issue Hydrodynamics and Heat Mass Transfer in Two-Phase Dispersed Flows in Pipes or Ducts)
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15 pages, 5222 KiB  
Article
Intense Vortex Motion in a Two-Phase Bioreactor
by Bulat R. Sharifullin, Sergey G. Skripkin, Igor V. Naumov, Zhigang Zuo, Bo Li and Vladimir N. Shtern
Water 2023, 15(1), 94; https://doi.org/10.3390/w15010094 - 28 Dec 2022
Cited by 4 | Viewed by 1724
Abstract
The paper reports the results of experimental and numerical studies of vortex motion in an industrial-scale glass bioreactor (volume, 8.5 L; reactor vessel diameter D, 190 mm) filled 50–80%. The model culture medium was a 65% aqueous glycerol solution with the density [...] Read more.
The paper reports the results of experimental and numerical studies of vortex motion in an industrial-scale glass bioreactor (volume, 8.5 L; reactor vessel diameter D, 190 mm) filled 50–80%. The model culture medium was a 65% aqueous glycerol solution with the density ρg = 1150 kg/m3 and kinematic viscosity νg = 15 mm2/s. The methods of particle image velocimetry and adaptive track visualization allow one to observe and measure the vortex motion of the culture medium. In this work, the vortex flow investigation was performed in a practical bioreactor at the operation regimes. Our research determines not only the optimal flow structure, but also the optimal activator rotation speed, which is especially important in the opaque biological culture. The main result is that, similar to the case of two rotating immiscible liquids, a strongly swirling jet is formed near the axis, and the entire flow acquires the pattern of a miniature gas–liquid tornado. The aerating gas interacts with the liquid only through the free surface, without any mixing. This intensifies the interphase mass transfer due to the high-speed motion of the aerating gas. Full article
(This article belongs to the Special Issue Hydrodynamics and Heat Mass Transfer in Two-Phase Dispersed Flows in Pipes or Ducts)
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13 pages, 5920 KiB  
Article
Flow Boiling Heat Transfer Intensification Due to Inner Surface Modification in Circular Mini-Channel
by Aleksandr V. Belyaev, Alexey V. Dedov, Nikita E. Sidel’nikov, Peixue Jiang, Aleksander N. Varava and Ruina Xu
Water 2022, 14(24), 4054; https://doi.org/10.3390/w14244054 - 12 Dec 2022
Cited by 4 | Viewed by 1331
Abstract
This work aimed to study the intensification of flow boiling heat transfer and critical heat flux (CHF) under conditions of highly reduced pressures due to a modification of the inner wall surface of a mini-channel. Such research is relevant to the growing need [...] Read more.
This work aimed to study the intensification of flow boiling heat transfer and critical heat flux (CHF) under conditions of highly reduced pressures due to a modification of the inner wall surface of a mini-channel. Such research is relevant to the growing need of high-tech industries in the development of compact and energy-efficient heat exchange devices. We present experimental results of the surface modification effect on hydrodynamics and flow boiling heat transfer, including data on the CHF. A description of the experimental stand and method for modifying the test mini-channel is also presented. The studies were carried out with freon R-125 in a vertical mini-channel with a diameter of 1.1 mm and a length of 50 mm, in the range of mass flow rates from G = 200 to 1400 kg/(m2s) and reduced pressures between pr = p/pcr = 0.43 and 0.56. The maximum surface modification effect was achieved at a reduced pressure of pr = 0.43, the heat transfer coefficient increased up to 110%, and the CHF increased up to 22%. Full article
(This article belongs to the Special Issue Hydrodynamics and Heat Mass Transfer in Two-Phase Dispersed Flows in Pipes or Ducts)
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18 pages, 5796 KiB  
Article
RANS Modeling of Turbulent Flow and Heat Transfer in a Droplet-Laden Mist Flow through a Ribbed Duct
by Maksim A. Pakhomov and Viktor I. Terekhov
Water 2022, 14(23), 3829; https://doi.org/10.3390/w14233829 - 24 Nov 2022
Cited by 3 | Viewed by 1322
Abstract
The local structure, turbulence, and heat transfer in a flat ribbed duct during the evaporation of water droplets in a gas flow were studied numerically using the Eulerian approach. The structure of a turbulent two-phase flow underwent significant changes in comparison with a [...] Read more.
The local structure, turbulence, and heat transfer in a flat ribbed duct during the evaporation of water droplets in a gas flow were studied numerically using the Eulerian approach. The structure of a turbulent two-phase flow underwent significant changes in comparison with a two-phase flow in a flat duct without ribs. The maximum value of gas-phase turbulence was obtained in the region of the downstream rib, and it was almost twice as high as the value of the kinetic energy of the turbulence between the ribs. Finely dispersed droplets with small Stokes numbers penetrated well into the region of flow separation and were observed over the duct cross section; they could leave the region between the ribs due to their low inertia. Large inertial droplets with large Stokes numbers were present only in the mixing layer and the flow core, and they accumulated close to the duct ribbed wall in the flow towards the downstream rib. An addition of evaporating water droplets caused a significant enhancement in the heat transfer (up to 2.5 times) in comparison with a single-phase flow in a ribbed channel. Full article
(This article belongs to the Special Issue Hydrodynamics and Heat Mass Transfer in Two-Phase Dispersed Flows in Pipes or Ducts)
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Review

Jump to: Editorial, Research

21 pages, 4568 KiB  
Review
Experimental Investigation of Mechanisms of Droplet Entrainment in Annular Gas-Liquid Flows: A Review
by Andrey V. Cherdantsev
Water 2022, 14(23), 3892; https://doi.org/10.3390/w14233892 - 29 Nov 2022
Cited by 7 | Viewed by 2197
Abstract
Entrainment of liquid from the film surface by high-velocity gas stream strongly affects mass, momentum and heat transfer in annular flow. The construction of basic assumptions for simplified physical models of the flow, as well as validation of numerical models, requires detailed experimental [...] Read more.
Entrainment of liquid from the film surface by high-velocity gas stream strongly affects mass, momentum and heat transfer in annular flow. The construction of basic assumptions for simplified physical models of the flow, as well as validation of numerical models, requires detailed experimental investigation of droplet entrainment process and the preceding stages of film surface evolution. The present paper analyzes the achievements and perspectives of application of various experimental approaches to qualitative and quantitative characterization of droplet entrainment. Optical visualization in at least two planes simultaneously may provide enough information on transitional liquid structures and detaching droplets, given that the side-view image is not obscured by the wall film. A planar LIF technique is not suitable for this purpose, since real objects are hidden by curved agitated interface and replaced by optical artifacts. To characterize the waves evolving into the transitional liquid structures, film thickness measurements in the plane of the wall are necessary. Such measurements can be achieved by intensity-based optical techniques, such as Brightness-Based LIF, near-infrared or X-ray attenuation techniques, combined with the side-view observations. Full article
(This article belongs to the Special Issue Hydrodynamics and Heat Mass Transfer in Two-Phase Dispersed Flows in Pipes or Ducts)
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30 pages, 5366 KiB  
Review
Two-Phase Annular Flow in Vertical Pipes: A Critical Review of Current Research Techniques and Progress
by Yunpeng Xue, Colin Stewart, David Kelly, David Campbell and Michael Gormley
Water 2022, 14(21), 3496; https://doi.org/10.3390/w14213496 - 01 Nov 2022
Cited by 10 | Viewed by 6583
Abstract
Two-phase annular flow in vertical pipes is one of the most common and important flow regimes in fluid mechanics, particularly in the field of building drainage systems where discharges to the vertical pipe are random and the flow is unsteady. With the development [...] Read more.
Two-phase annular flow in vertical pipes is one of the most common and important flow regimes in fluid mechanics, particularly in the field of building drainage systems where discharges to the vertical pipe are random and the flow is unsteady. With the development of experimental techniques and analytical methods, the understanding of the fundamental mechanism of the annular two-phase flow has been significantly advanced, such as liquid film development, evolution of the disturbance wave, and droplet entrainment mechanism. Despite the hundreds of papers published so far, the mechanism of annular flow remains incompletely understood. Therefore, this paper summarizes the research on two-phase annular flow in vertical pipes mainly in the last two decades. The review is mainly divided into two parts, i.e., the investigation methodologies and the advancement of knowledge. Different experimental techniques and numerical simulations are compared to highlight their advantages and challenges. Advanced underpinning physics of the mechanism is summarized in several groups including the wavy liquid film, droplet behaviour, entrainment and void fraction. Challenges and recommendations are summarized based on the literature cited in this review. Full article
(This article belongs to the Special Issue Hydrodynamics and Heat Mass Transfer in Two-Phase Dispersed Flows in Pipes or Ducts)
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